Agentic - Invocation Model Enhancements

[cescoffier]

• Rename AgentInvocation to Invocation/Action to enable invocations of regular methods/tools
• Study retry, rollback (compensation), and durability mechanisms, especially in function calling, and whether these should be managed at the planner level or execution level
• Improve human-in-the-loop and agent conversation support

From quarkusio/quarkus#50582.